Detect if a web site is already open and reuse window - php

I'm trying to find out if there is a way to open a url link in an email and reuse a window if a certain page ( or site ) is already open.
What I have is a 'forgot password' page where the user enters their email address and gets asked a security question, this then sends a plain text email with a url link (so no html link attributes) and reports to the user that it has done a good job . When the user clicks on the link it opens up a shiney new browser window and ignores the old report page leaving it feeling sad and unwanted. I would like to know if there is a way to reuse this window or more specifically the forgot password report page. Perhaps I could name the page with javascript or detect if the url is already open somehow.
Or is it possible if I did decide to use an html email, so most people would get the benefit.
Please help my report page to loved and wanted again.
Thanks
I am using PHP and I could use javascript or jquery browserside, or anything else that might fit in with this

This is completely up to the browser to decide; some browsers might be able to guess what you're trying to do and replace an existing tab with the new page, but on the whole that doesn't make sense.
This is what you could do (though it's not really technical):
after the email is entered and submitted, the form page changes and asks them for the security code that's being sent to them.
inside the email you print the security code in a clear manner for the user to double-click and copy to their clipboard; they would then switch to their browser again (with your page still open) and paste the value. You can still provide the link for ease of the user, of course.
Btw, to make an easily selectable code for the user to copy into their clipboard I found that using base32 encoding is the best; those codes can be selected easily, even with iOS devices.

You could have the page opened by the email send out a postMessage request and have the other page answer that is is still open. If that happened, the new tab could close immediately.
However, switching between tabs/windows is something happens at the OS or browser level, not the page level, and there is no way to switch to the open tab using JavaScript. You could write a browser extension to do it, but that's probably innapropriate for something so trivial, and no one would bother to install it.

Related

How to disable browser back history for a specific route in php? [duplicate]

I am working on a my site to allow users to take test so they can see how much they know of a particular subject. I am running into a little problem though. Once a user submits the test for grading, how do I prevent them from going back to the test page? I am on a Mac with Safari running and when I click the back button in my web browser after I submit the test it leaves all of the answers I answered filled out. I want it do this: When a user submits a test and they click the back button in their web browser it redirects them to the main test page.
I am using PHP and MYSQL. I even have the test pages setup so that the user must come from a certain url (I am using HTTP_REFERER) and I have tried other stuff such as sessions but I cannot seem to figure this out. Any help is greatly appreciated.
You don't stop them.
Instead change your application so that it still works even if they go back. You can embed a unique number in a hidden field on the page and if they resubmit the same test twice you can detect it and display an appropriate error message. You should also think about what should happen if they modify the unique number.
If you don't want people to post different answers once they have already answered, all you have to do is check, in the script that accepts the test for grading, that the user has never submitted the test before. If you don't, a clever student will always be able to to circumvent your protection by sending an appropriate request directly to that script.
If you don't want people to see previous answers (for instance, if you have two people grade their tests on the same computer), consider using AJAX on the test page to submit the answers and then erase them from the fields. This way, most browsers will not remember the answers and the back button will not un-erase data that was erased by JavaScript.
At the top of the grade page, put the following:
session_start();
$_SESSION['testcomplete'] = 'yes';
Then at the top of each page of the test, put this:
session_start()
if ($_SESSION['testcomplete'] == 'yes') {
header("Location:cheater.php");
}
You could simulate there being no page to go back to. From one page, generate each test page using jQuery, and provide no way to go back, only forward. The back button would take them to the page before they ever launched the test, and you could allow them to launch the test again and generate the right part where they should be. This would be pretty easy, if you haven't gone too far in development the current way.
You could run javascript that clears out all the answers. You might also just allow one submission so that subsequent submissions don't get processed. HTTP_REFERER is usually sent, but can be spoofed and forged by an altered browser.
On the top of the script POST-ing the answers, do a check whether you have the test results in the database for the current user for this test. If you do, redirect to results.
if(get_test_results($user)){
$test_url = get_test_url($user);
header( "Location: $test_url" ) ;
}
Disabling the back button is not a good idea.
I was facing a similar problem making an online examination myself
what I did is
I provided a session variable such that if the user pastes the previous page's URL in the address bar then on loading the page the page is automatically forwards to the next desired page. Whether the page whose URL was mentioned is the being visited the first time or being revisited is determined by the value of the session variable
If the user instead of loading the page does a go back via the browser button the it automatically redirects to the next page in history as :
javascript:window.history.forward(1);
Hope this helps :)
http://www.htmlgoodies.com/tutorials/buttons/article.php/3478911/Disabling-the-Back-Button.htm you should be able to do it in javascript.

How can I prevent the user to go back to my shop checkout with the "back" button of the browser? [duplicate]

I am working on a my site to allow users to take test so they can see how much they know of a particular subject. I am running into a little problem though. Once a user submits the test for grading, how do I prevent them from going back to the test page? I am on a Mac with Safari running and when I click the back button in my web browser after I submit the test it leaves all of the answers I answered filled out. I want it do this: When a user submits a test and they click the back button in their web browser it redirects them to the main test page.
I am using PHP and MYSQL. I even have the test pages setup so that the user must come from a certain url (I am using HTTP_REFERER) and I have tried other stuff such as sessions but I cannot seem to figure this out. Any help is greatly appreciated.
You don't stop them.
Instead change your application so that it still works even if they go back. You can embed a unique number in a hidden field on the page and if they resubmit the same test twice you can detect it and display an appropriate error message. You should also think about what should happen if they modify the unique number.
If you don't want people to post different answers once they have already answered, all you have to do is check, in the script that accepts the test for grading, that the user has never submitted the test before. If you don't, a clever student will always be able to to circumvent your protection by sending an appropriate request directly to that script.
If you don't want people to see previous answers (for instance, if you have two people grade their tests on the same computer), consider using AJAX on the test page to submit the answers and then erase them from the fields. This way, most browsers will not remember the answers and the back button will not un-erase data that was erased by JavaScript.
At the top of the grade page, put the following:
session_start();
$_SESSION['testcomplete'] = 'yes';
Then at the top of each page of the test, put this:
session_start()
if ($_SESSION['testcomplete'] == 'yes') {
header("Location:cheater.php");
}
You could simulate there being no page to go back to. From one page, generate each test page using jQuery, and provide no way to go back, only forward. The back button would take them to the page before they ever launched the test, and you could allow them to launch the test again and generate the right part where they should be. This would be pretty easy, if you haven't gone too far in development the current way.
You could run javascript that clears out all the answers. You might also just allow one submission so that subsequent submissions don't get processed. HTTP_REFERER is usually sent, but can be spoofed and forged by an altered browser.
On the top of the script POST-ing the answers, do a check whether you have the test results in the database for the current user for this test. If you do, redirect to results.
if(get_test_results($user)){
$test_url = get_test_url($user);
header( "Location: $test_url" ) ;
}
Disabling the back button is not a good idea.
I was facing a similar problem making an online examination myself
what I did is
I provided a session variable such that if the user pastes the previous page's URL in the address bar then on loading the page the page is automatically forwards to the next desired page. Whether the page whose URL was mentioned is the being visited the first time or being revisited is determined by the value of the session variable
If the user instead of loading the page does a go back via the browser button the it automatically redirects to the next page in history as :
javascript:window.history.forward(1);
Hope this helps :)
http://www.htmlgoodies.com/tutorials/buttons/article.php/3478911/Disabling-the-Back-Button.htm you should be able to do it in javascript.

Simultaneous redirect to App Store and another page

After having completed an online registration process, I want to check if the user is using an iPhone, and in that case give the option of opening App Store to download the app. Here's what I've coded so far:
In PHP, check $_SERVER['HTTP_USER_AGENT'] for the presence of the substring "iPhone".
If so, output JavaScript code that, before redirecting to the welcome page, offers the possibility of going to App Store using a confirm box.
Redirect to itms-apps://itunes.apple.com/url-to-my-app using window.location = ... in JavaScript.
This works. However, when the user once again opens Safari, the page which I redirected from is still open. This doesn't make any sense in my case. I want to redirect to the welcome page regardless of whether the user chooses to open the App Store. If I try to write another window.location line below the first one to perform a second redirect, Safari simply skips the link to the App Store.
I've considered redirecting from a hidden iframe, placing some kind of timer on the second redirect, experimenting with different combinations of JavaScript and HTTP header redirects and so on. None of the solutions I've thought of so far seems really solid, though. How do I do this if I want it to work gracefully across browsers and versions?
The only way to do this is to use the welcome page itself to do the iTunes redirect.

Implementing captcha only once for one session

I've been working on a website which contains alot of links. I want to protect those links from bots/crawlers by implementing a CAPTCHA. I've tried reCAPTCHA by Google but it doesn't suit my needs(complex specially when it comes to people who are poor in English :P) plus I just want to stop the new programmers or crawlers, I know it can easily be broken by experienced programmers. So I searched and found this one to be good.
http://www.hardcode.nl/subcategory_4/article_243-simple-php-captcha-script.htm
Downloaded it and its working like a charm but my problem is :
1. I can see the index.html files checks the entered code and if correct redirects to write.php where session is created and output is shown. I want this to be done on the same page. Like when user enters correct code, he should be able to view the view the links on the same page to save bandwidth (I'll fetch them from mysql server)
2. This is more important one, since I don't know anything about php sessions and php.net tutorials are just too short or next to nothing, can this be done that whenever a user input correct captcha once, he can see the links for rest of the time without captcha? And he will have to re-enter the captcha only when he closes the browser or after some interval like 10 minutes in case previous one can't be done.
Thank you
PS. I can use Javascript on my server but probably a php solution will be better since I'm also learning php
Use AJAX to pull the links and then replace the HTML in the page.
Store a variable in the session that determines whether or not they've entered a CAPTCHA, then just check that before deciding whether to show the CAPTCHA or the links.

Detect new $_SESSION variable without refresh. Maybe AJAX?

I'm currently building a website which fetches youtube videos and flickr images and lets users comment on them on the website. While having it's own commenting system, the website also has an option to login with youtube/flickr to comment on youtube or flickr with their usernames.
I'm doing this by opening a popup window (real popup, not a jquery kind of popup), closing the popup after they login and storing their tokens in a PHP $_SESSION. Question is, I have quite a lot of stuff going on with jQuery and I'd like to let them switch between commenting as a visitor to the site to commenting on Flickr/YouTube after they login without refresh.
Basically, I'd need a way to detect when the pop-up closes so I could then make a request to a PHP file which would tell me if the user has a token saved in the $_SESSION or not and hide the name and email boxes from the comment form as they would only need the input box.
Another way would be to trigger a setInterval() when they open the popup and check for the $_SESSION every 2/3 seconds for example, but I don't think that's the best way to go. Ideally I'd want something that works as soon as the user closes the popup.
More details:
I'm using http://swip.codylindley.com/popupWindowDemo.html to display the pop-ups
The callback script for both functions does a self.close() after storing the token in a $_SESSION
Users can be logged in with both Flickr and Youtube (but I don't think this matters anymore).
Difference between commenting as a visitor and Flickr/Youtube user is that you have three fields (name, email, message) as a visitor and just one otherwise (message)
I do a check when page loads, so if the user refreshes the page at this point, everything is ok, but I would like it if he didn't have to do that, or if at least it would refresh automatically.
Lastly, I'm good to go with other options, as long as the user doesn't have to leave the page, refresh himself to swap between visitor and logged in user. Using jQuery in the page so if it's a jQuery based solution, even better.
Sorry for the long post, couldn't find a way to make it shorter.
Thank you for the help guys!
EDIT
setInterval() with a function that calls a PHP script to check for the $_SESSION variable worked like a charm, not at all as bad on performance or user experience as I expected. Still, if anyone can think of a better solution I'm ready to accept it.
Thanks!
You could place in the pop-window HTML code:
<body onunload="window.opener.location.href = 'http://check.session.com/path/to/file.php'">

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